By ANDREW POLLACK

Published: September 8, 2006

CORRECTION APPENDED

More miles to the bushel.

That is the new mission of crop scientists. In an era of $3-a-gallon gasoline and growing concern about global warming from fossil fuels, seed and biotechnology companies see a big new opportunity in developing corn and other crops tailored for use in ethanol and other biofuels.

Syngenta, for instance, hopes in 2008 to begin selling a genetically engineered corn designed to help convert itself into ethanol. Each kernel of this self-processing corn contains an enzyme that must otherwise be added separately at the ethanol factory.

Just last week, DuPont and Bunge announced that their existing joint venture to improve soybeans for food would also start designing beans for biodiesel fuel and other industrial uses.

And Ceres, a plant genetics company in California, is at work on turning switch grass, a Prairie States native, into an energy crop.

''You could turn Oklahoma into an OPEC member by converting all its farmland to switch grass,'' said Richard W. Hamilton, the Ceres chief executive.

Developing energy crops could mean new applications of genetic engineering, which for years has been aimed at making plants resistant to insects and herbicides, but would now include altering their fundamental structure. One goal, for example, is to reduce the amount of lignin, a substance that gives plants the stiffness to stand upright but interferes with turning a plant's cellulose into ethanol.

Such prospects are starting to alarm some environmentalists, who worry that altered plants will cross-pollinate in the wild, resulting in forests that practically droop for want of lignin. And some oppose the notion of altering corn to feed the nation's addiction to automobiles.

''I don't think people want extra enzymes in the food supply put there to better fit the crops for energy production,'' said Margaret Mellon, director of the food and environment program at the Union of Concerned Scientists.

But proponents of designer fuel crops argue that the risks are small compared with the threat of dependence on foreign oil. Some studies also suggest that ethanol use could help fight global warming because the crops that help produce ethanol absorb carbon dioxide.

So far, much of the attention on bioenergy has focused on improving the chemical processes for turning crops into ethanol. But experts say that if biofuels are to make a significant dent in the nation's petroleum consumption, the crops themselves must be improved to provide more energy from an acre.

And new agricultural sources beyond corn must be developed, they say. Even if the nation's entire corn crop were converted to ethanol production, it would replace only about 15 percent of petroleum use, according to an Energy Department report.

''Half the improvement we make over the next 10 to 15 years will come from improving the feedstocks,'' said Gerald A. Tuskan, a biofuel expert in the department, referring to the crops fed into the ethanol factories.

Some of the work will not necessarily involve genetic engineering. Notably, Monsanto, the leader by far in crop biotechnology, says that its biofuel development will focus on conventional breeding, which it says is quicker.

Monsanto has tested its existing corn varieties to determine which ones are better for ethanol production. Pioneer Hi-Bred International, the DuPont subsidiary that is Monsanto's rival in the corn-seed business, is doing the same.

The companies say that the designated varieties, which have higher fermentable starch content, can increase ethanol production 2 to 5 percent over other corn. And some factories are starting to request certain types of corn or to pay a premium for more desirable corn, said Pradip Das, head of crop analytics at Monsanto.

Still, some ethanol factory operators say they do not really care which corn they get. The factories are so hungry that they take ''pretty much all the commercial corn you can get your hands on,'' said David Nelson, chairman of Midwest Grain Processors, which runs an ethanol plant in Lakota, Iowa.

William S. Niebur, vice president for crop genetics research and development at DuPont, said the demands of ethanol production would require extremely hardy corn.

''The demand for this corn grain could be so dramatic,'' he said, ''that it would change farming practices.'' Instead of rotating corn with other crops, he said, farmers would be pressed to grow corn year after year, which could strain the soil and allow the buildup of insects and disease.

Many of the traits needed for energy corn -- high yield as well as tolerance to disease, insects and drought -- would also be desirable in corn used for human and animal food. That is not the case, though, with Syngenta's enzyme corn, which would be specifically for energy production.

Generally, the enzyme, known as amylase, is made in vats of bacteria. Ethanol manufacturers add the enzyme to corn to break down starch into sugar, which can be fermented into ethanol.

To get corn to produce its own amylase, Syngenta inserted a gene borrowed from a type of microbe called archaea that live near hot-water vents on the floor of the ocean.

Correction: September 15, 2006, Friday
An article in Business Day last Friday about the development of crops for energy production misstated a figure on ethanol conversion from a Department of Energy report. The report said that even if the nation's entire corn crop was converted to ethanol, it would replace only 15 percent of the nation's transportation fuel needs -- not its overall petroleum needs.